Valvular heart disease among non-valvular atrial fibrillation: a misnomer, in search of a new term.

A 76-year-old male patient with arterial hypertension and moderate aortic stenosis presents with the first episode of atrial fibrillation (AF). His CHA2DS2-VASC score is 3. Can we use the CHA2DS2VASC score that has been developed in patients with non-valvular AF for assessment of his need for long-term oral anticoagulation? Also, since the underlying trials were done in patients with nonvalvular AF, is this patient eligible for a non-vitamin K antagonist (NOAC) or does he have valvular disease and, thus, would need a vitamin K antagonist? These are frequently raised questions among cardiologists. Based on registry data, patients with AF and valve disease are common in clinical practice, 6 with a higher proportion of these patients among those with permanent than those with paroxysmal or persistent AF (Table 1). While the prevalence was reported as 21% in the Euro Heart Survey (defined as ‘any type of valve disease’) and 24.6% in AFNET (‘non-rheumatic valve disease’), it was only 4.2% in the PREvention oF thromboembolic events-European Registry in Atrial Fibrillation (PREFER in AF). The aim of the latter registry was to assess the management of AF in European countries after the publication of the 2010 European Society of Cardiology (ESC) Guidelines on AF which preferably addressed non-valvular AF. Thus, there may be a gap between the focus of the guidelines and the situation in clinical practice. Differences in the composition of patient cohorts in registries may be due to the presentation of different patient categories to the recruiting units, to differences in entry criteria into a registry, as well as to the selection of centres. For instance, the aim of the Euro Heart Survey was to assess the care of patients in cardiological units, whereas it was the explicit aim to mirror the type and quality of care on all levels of the healthcare system (from general practitioners to specialized tertiary cardiology centres) in the German AFNET registry. However, differences in patient cohorts may also reflect different interpretation of the definition of non-valvular AF when recruiting patients. The ACC/AHA/ESC Guidelines 2006 defined non-valvular AF as AF in the absence of rheumatic mitral valve disease, prosthetic heart valves, or valve repair. The 2012 focused update of the ESC Guidelines states that it is conventional to divide AF into cases which are described as ‘valvular or ‘non-valvular’. Valvular AF was defined as rheumatic valvular disease (predominantly mitral stenosis) or prosthetic heart valves. Similarly, the 2014 AHA/ACC/HRS Guideline for the management of patients with AF defined nonvalvular AF as AF in the absence of rheumatic mitral stenosis, or a mechanical heart valve, but explicitly added bioprosthetic heart valves or mitral valve repair (Figure 1). In clinical practice, the term non-valvular AF has created considerable confusion among physicians who use it to ask which patients fall into which category and may be treated by novel anticoagulants. This has been confirmed in a recent prospectively conducted web-based survey of cardiologists and internists. Co-existence of both medical history of rheumatic disease and clinical signs of valvular involvement were considered as essential prerequisites for the diagnosis of rheumatic AF by half of the respondents, and one-third assumed that lone aortic valve disease was sufficient for AF to be defined as valvular. A similar proportion of respondents considered that in the presence of mitral regurgitation, AF had to be defined as valvular. The majority of responding physicians considered the degree of valvular disease of lesser importance for the definition of valvular or non-valvular origin of AF. Proper understanding of which type of valve disease belongs to non-valvular AF is critical when considering the use of an NOAC in patients with AF. The importance of restricting the indications to available trial data has been shown by the RE-ALIGN study which advises against the use of the NOAC dabigatran in patients with mechanical heart valve prostheses. Recent trials on NOACs and the labelling of their respective compounds by the European Medicines Agency refer to non-valvular AF as an indication for dabigatran, rivaroxaban, and apixaban to prevent ischaemic stroke and systemic embolism. Despite apparent